Project objectives are to study the activities of Na, K, Ca, Mg, and NH4 ions and their relationship to contractile responsesin dog bladder and ureteral muscle. In vitro isometric muscle chamber preparations of bladder and ureteral muscle are used. Current experiments include analysis of Ca activity in detrusor strips subjected to bethanechol, KC1, and NH4-induced contractile activity. The effect of bacteria and infection on cation behavior related to detrusor contractile activity is also being studied.